Mr. Jim Callaghanasked the Secretary of State for Transport what criteria he uses to determine the economic value of a motorway; and at what point a motorway scheme is deemed economically non-viable.
§ Mr. Kenneth ClarkeThe economic component of the assessment of new roads compares the present values of the construction and net maintenance costs with the savings in time. vehicle operating costs, and accident costs using a discount rate of 7 per cent. per annum. The economic benefits are assessed on the basis of a range of assumptions about future economic growth and fuel prices. The "viability" or desirability of a scheme is not decided on its economic return alone. The judgment also has to take account of environmental advantages and disadvantages and wider planning and regional economic policies.